Electrical Systems-SLO

1. Volts, amps, and ohms are the three basic units of electrical measurement.

True

False

Voltage, amperage, and resistance are the 3 main electrical measurements.

Explanation

Voltage, amperage, and resistance are the 3 main electrical measurements.

2. In calculating ohm's law:

R stands for resistance.

A stands for amps.

V stands for voltage.

All of the above

All of the above are correct.

Explanation

All of the above are correct.

3. A switch is used to:

Protect a circuit.

Allow current to flow only one way.

Reduce the current flow.

Turn current flow on and off.

A switch controls the current flow to the resistor.

Explanation

A switch controls the current flow to the resistor.

4. Ohm's law tells us that it takes 1 volt to push 1 amp through how many ohms?

1

2

3

4

Solve volts = amps x resistance.

Explanation

Solve volts = amps x resistance.

5. Tech A says you must have power supply for a simple circuit to work. Tech B says a switch will interrupt. Who is correct?

Tech A

Tech B

Both Techs A and B

Neither Tech A nor B

The power supply is one of the components of a simple circuit. The switch interrupts the current in a circuit.

Explanation

The power supply is one of the components of a simple circuit. The switch interrupts the current in a circuit.

6. What materials make a good insulator?

Copper and aluminum

Ceramic and plastic

Both A and B

None of the above

Ceramics, plastics and rubbers are good insulators. They do not readily accept or give electrons.

Explanation

Ceramics, plastics and rubbers are good insulators. They do not readily accept or give electrons.

7. Controlled area network bus (CAN-bus) systems carry:

Children.

High-speed data.

Very slow data.

Info for the cruise control.

The data in a CAN is at a very high speed with respect to other data transfer in a vehicle.

Explanation

The data in a CAN is at a very high speed with respect to other data transfer in a vehicle.

8. Tech A says a solenoid is not used on modern automobiles. Tech B says fuel injectors and starter motor solenoids are two of many solenoids used on modern automobiles. Who is correct?

Tech A

Tech B

Both Techs A and B

Neither Tech A nor B

Solenoids are used in many automotive applications, injectors and starter motors are 2 of these uses.

Explanation

Solenoids are used in many automotive applications, injectors and starter motors are 2 of these uses.

9. You have a 4 ohm resister and the battery is charged to 12 volts. How many amps will flow in the circuit?

1

2

3

4

Solve volts = amps x resistance.

Explanation

Solve volts = amps x resistance.

10. Tech A says when you ground a circuit, you hook it back to the positive side of the battery. Tech B says some manufactures use the chassis as a return path to the battery. Who is correct?

Tech A

Tech B

Both Techs A and B

Neither Tech A nor B

Grounding is the act of completing the circuit to the negative part of the battery. Since the battery ground hooks up to the chassis, it can be used as a universal ground for the vehicle.

Explanation

Grounding is the act of completing the circuit to the negative part of the battery. Since the battery ground hooks up to the chassis, it can be used as a universal ground for the vehicle.

11. Tech A says an alternator has to have a transformer and a rectifier is used to produce DC volts. Tech B says you can run an AC motor on DC volts. Who is correct?

Tech A

Tech B

Both Techs A and B

Neither Tech A nor B

Alternators create AC voltage and need to be rectified to DC to be used in automobiles. You can not run an AC motor on DC volts, and vise versa.

Explanation

Alternators create AC voltage and need to be rectified to DC to be used in automobiles. You can not run an AC motor on DC volts, and vise versa.

12. How many paths are there in a series circuit?

1

2

3

4

A series circuit is when the resistances are sequentially in line with each other.

Explanation

A series circuit is when the resistances are sequentially in line with each other.

13. Tech A says wire size is very important. Tech B says there are two scales used to measure wire size. Who is correct?

Tech A

Tech B

Both Techs A and B

Neither Tech A nor B

Wire size is very important. That is why the starter cables are the size they are. There are many gauges of wire size.

Explanation

Wire size is very important. That is why the starter cables are the size they are. There are many gauges of wire size.

14. Electrochemical energy is produced when:

The sun shines on photocells.

The steam builds.

When two dissimilar metals are heated.

Two dissimilar metals are immersed in an acidic liquid.

The reaction between the acid and the lead is what creates the movement of electrons.

Explanation

The reaction between the acid and the lead is what creates the movement of electrons.

15. Tech A says parallel circuits are like links in a chain. Tech B says total current in a parallel circuit equals the sum of the current flowing in each branch of the circuit. Who is correct?

Tech A

Tech B

Both Techs A and B

Neither Tech A nor B

Parallel circuits are when the resistances are side by side, with individual power supplies and grounds. The sum of all of the current draws in a parallel circuit is the total current draw in the circuit.

Explanation

Parallel circuits are when the resistances are side by side, with individual power supplies and grounds. The sum of all of the current draws in a parallel circuit is the total current draw in the circuit.

16. Tech A says copper has a low resistance. Tech B says the length of wire doesn't affect resistance. Who is correct?

Tech A

Tech B

Both Techs A and B

Neither Tech A nor B

Copper has a low resistance. That is why it is used to carry electricity. Both the length and width of a wire will effect the amount of resistance it has.

Explanation

Copper has a low resistance. That is why it is used to carry electricity. Both the length and width of a wire will effect the amount of resistance it has.

17. Tech A says an atom with more electrons than protons has an overall positive charge. Tech B says not all atoms can give up or accept electrons easily. Who is correct?

Tech A

Tech B

Both Techs A and B

Neither Tech A nor B

The charge of electrons and protons in an atom cancel each other. Some atoms are already "happy", others want to accept electrons, and others what to give up theirs to have 8 valence electrons.

Explanation

The charge of electrons and protons in an atom cancel each other. Some atoms are already "happy", others want to accept electrons, and others what to give up theirs to have 8 valence electrons.

18. Tech A says high resistance causes an increase in current flow. Tech B says a voltage drop is another name for high resistance. Who is correct?

Tech A

Tech B

Both Techs A and B

Neither Tech A nor B

High resistance does not increase current flow. Solve ohms law for constant voltage and infinite resistance. The drop of voltage in a circuit is a measurement of how much resistance there is in the part of the circuit being measured.

Explanation

High resistance does not increase current flow. Solve ohms law for constant voltage and infinite resistance. The drop of voltage in a circuit is a measurement of how much resistance there is in the part of the circuit being measured.

19. Tech A says a resistor is a component designed to extract energy from the current flow. Tech B says he uses a voltmeter to check for a voltage drop. Who is correct?

Tech A

Tech B

Both Techs A and B

Neither Tech A nor B

Resistors or loads eat up the energy from the source. A voltmeter is used to measure the drop of voltage through a circuit.

Explanation

Resistors or loads eat up the energy from the source. A voltmeter is used to measure the drop of voltage through a circuit.

20. Tech A says relays are turned on and off by a small amount of current. Tech B says there are two types of relays: normally closed (NC) and normally open (NO) types. Who is correct?

Tech A

Tech B

Both Techs A and B

Neither Tech A nor B

A small amount of current is used to energize the windings in a relay. They can either be normally open or closed.

Explanation

A small amount of current is used to energize the windings in a relay. They can either be normally open or closed.

21. What are the three types of resistors?

Rheostats, potentiometers, thermistors

Fixed, fluid, thermistors

Round, square, triangle

Thermistors, negative temperature coefficient (NTC) thermistor resistance, positive temperature coefficient (PTC) thermistor resistance

Three different types of resistors are listed in option A.

Explanation

Three different types of resistors are listed in option A.

22. All of the following could cause a slow cranking condition EXCEPT:

Over-advanced ignition timing

Shorted neutral safety switch

Misaligned starter mounting

Low battery state of charge

A shorted neutral safety switch could cause a slow cranking condition. The neutral safety switch is responsible for preventing the vehicle from starting in any gear other than park or neutral. If the switch is shorted, it may not properly engage or disengage, causing the starter to struggle when trying to crank the engine. On the other hand, over-advanced ignition timing, misaligned starter mounting, and a low battery state of charge can all contribute to a slow cranking condition.

Explanation

A shorted neutral safety switch could cause a slow cranking condition. The neutral safety switch is responsible for preventing the vehicle from starting in any gear other than park or neutral. If the switch is shorted, it may not properly engage or disengage, causing the starter to struggle when trying to crank the engine. On the other hand, over-advanced ignition timing, misaligned starter mounting, and a low battery state of charge can all contribute to a slow cranking condition.

23. Tech A says in a parallel circuit, the more branches that are added, the more current flow increases. Tech B says a series-parallel circuit is made of parallel circuits only. Who is correct?

Tech A

Tech B

Both Techs A and B

Neither Tech A nor B

The sum of the currents in a parallel circuit equal the total draw of current. A series-parallel circuit is exactly that, a circuit with resistors in series and parallel.

Explanation

The sum of the currents in a parallel circuit equal the total draw of current. A series-parallel circuit is exactly that, a circuit with resistors in series and parallel.

24. Controlled area network bus (CAN-bus) systems should be checked using a(n):

Power probe

Analog meter

Test light

Digital multimeter

CANs can be checked with either a digital multimeter or an osciliscope.

Explanation

CANs can be checked with either a digital multimeter or an osciliscope.

25. During an output test using the full field method, a 100 ampere alternator with an integral regulator produces 60 amps. The cause of the low alternator output could be a(n):

Shorted diode in the alternator

Broken brush lead wire in the alternator

Open circuit in the voltage regulator

Defective alternator capacitor

A shorted diode in the alternator can cause a low alternator output. Diodes in an alternator are responsible for converting AC voltage to DC voltage. When a diode becomes shorted, it allows current to flow in the wrong direction, resulting in a decrease in the overall output of the alternator. This leads to a lower amperage being produced, which explains why the 100 ampere alternator is only producing 60 amps.

Explanation

A shorted diode in the alternator can cause a low alternator output. Diodes in an alternator are responsible for converting AC voltage to DC voltage. When a diode becomes shorted, it allows current to flow in the wrong direction, resulting in a decrease in the overall output of the alternator. This leads to a lower amperage being produced, which explains why the 100 ampere alternator is only producing 60 amps.

26. Tech A says fiber optic cables are more expensive and very heavy. Tech B says fiber optics can only carry very little data. Who is correct?

Tech A

Tech B

Both Techs A and B

Neither Tech A nor B

Fiber optic cables are made from plastic. They are very light and cheap to make. Pulses of light have the ability to transfer a large amount of data, very quickly, and with very little energy used.

Explanation

Fiber optic cables are made from plastic. They are very light and cheap to make. Pulses of light have the ability to transfer a large amount of data, very quickly, and with very little energy used.